The present invention relates to a press in general, and more particularly to a rapid-cycle press.
Still more particularly, the invention relates to a rapid-cycle press for coating sheets, panels and similar workpieces.
Generally speaking, presses of this type have an upper and a lower press table which can be moved apart so that a workpiece can be placed between them. Thereupon the press plates are moved together to exert pressure upon the workpiece and they are then moved apart again. Presses of this type are widely used to coat panels and similar workpieces, such as chipboard panels, with any of a variety of surfacing materials. For example, melamine films or films on the basis of phenyolic resin or the like are applied in this manner under the influence of heat and pressure to the surfaces of such panels.
A press of this type is known from German Pat. No. 1,911,764, which discloses that the workpieces can be introduced into the press gap, i.e. the space between the two press plates when the press is open, by means of roller-belt conveyors, and the finished workpieces are removed from this gap with the aid of transporting frames having suction elements thereon. The workpieces to be processed in these presses are usually of relatively large dimensions which means that the transporting frames must have a rather large number of such suction elements and this in turn requires a rather substantial mechanical expenditure as well as the expenses for providing control equipment which controls the operation of these suction elements. Particularly, the expenses of the control equipment increase the price of the press very substantially and thus commensurately decrease the economy involved in its acquisition and operation.
In view of this it has been proposed to simplify the removal of the finished workpieces from these presses by just not lifting the finished workpieces off the lower press plate, but pulling or pushing the finished workpiece out of the opened press and letting it slide along on the lower press plate. Unfortunately, this results very quickly in the formation of the sided tracks in the highly polished surface of the lower press plate so that either the entire lower press plate, or at least that portion of it provided with the highly polished surface, quickly becomes unusable and must be replaced.